The bladder is an internal organ located in the pelvis, and serves as a kind of pouch, in which urine is stored temporarily after it is made in the kidney and then transported via the pelvis of the kidney and the ureter. If the bladder expands due to the urine stored therein, one feels a need to urinate and then passes urine. Upon passing urine, muscles of the bladder shrink to discharge urine completely. The surface of the bladder is covered with an epithelium referred to as the transitional epithelium, and is characterized by showing excellent elasticity. The bladder tumor occurs during the conversion of the transitional epithelium into a tumor. Most bladder tumors (90% or more) are transitional epithelial cell carcinomas. In Korea, bladder tumors are the most frequent among cancers occurring in the urinogenital organs. The incidence of bladder cancer is 7.76 per 100,000 for man and 1.19 per 100,000 for woman. In Korea, bladder tumors are the fourth occurring cancer in man. Actually, about 70% of bladder tumors are superficial, 20% thereof are invasive only to the bladder, and 10% thereof are metastatic. About 70% of superficial bladder tumors are recurred, wherein most of recurred bladder tumors are superficial, and 10-15% thereof proceeds into invasive or metastatic bladder tumors. About 30% of superficial bladder tumors are not recurred and have no problem in convalescence. However, 10-15% of superficial bladder tumors occasionally proceed into invasive or metastatic tumors despite of various therapies.
Heretofore, diagnosis of a bladder tumor has been performed by cytology of bladder, which comprises staining cells separated from urine via a Pap (Papanicolau) staining method and observing the shape of each cell with a microscope to screen a tumor cell, and by endoscopy of bladder, which comprises screening a tumor directly inside bladder through an endoscope. The cytology has an advantage of a correct diagnosis of a tumor cell, once the tumor cell is found, while having disadvantages of a great possibility of failing to notice tumor cells and time-consuming. On the other hand, the endoscopy of bladder has a disadvantage of putting subject into inconvenience while inserting an endoscope into the bladder through urethra. Therefore, it is necessary to provide a novel diagnosis method that solves the aforementioned problems occurring in the prior art, and a diagnosis system that can be used for the same diagnosis method.
Meanwhile, drug delivery systems or targeting therapies, by which drugs are delivered selectively to tumors, are interested. This is because drug delivery systems or the targeting therapies can provide an increased drug efficacy under the same amount of an anti-tumor agent, and significantly reduced side effects adversely affecting normal tissue. Additionally, when such systems or therapies are applied to gene therapy, it is possible to increase the efficiency of treatment and to reduce serious side effects by virtue of the selective delivery of virus to tumor cells. For this, many attempts have been made to develop an antigen specific to a tumor cell and an antibody for targeting the antigen. However, such antibody has problems of possibility of immune responses and a low tissue-infiltration efficiency. On the other hand, peptides have a low molecular weight, and thus having low possibility of immune responses and high tissue-infiltration efficiency. Therefore, the combination of a tumor-targeting peptide with a conventional anti-tumor agent can provide an intelligent drug carrier capable of selective drug delivery to a tumor. Under these circumstances, there has been a continuous need to develop a novel tumor-targeting peptide.